971 resultados para AGRICULTURAL PRODUCTIVITY


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A clean and healthy environment is paramount to human existence. While pesticide use has successfully sustained agricultural and food production in our lifetime as well as safeguarded human health by controlling insect pests, it has also caused many tragedies including population declines in our wildlife, fatalities in workers exposed to pesticides in its manufacture and use, and the increasing incidence of dreaded human illnesses such as cancer. A delicate balance should be achieved to mitigate the adverse impact of pesticide use to the environment and at the same time ensuring short- and long-term agricultural productivity. Endosulfan has been effectively used as a pesticide, but much evidence on its chronic and sub-lethal effects on humans and wildlife have been gathered in recent years. More research still needs to be done to determine its effects from long-term exposure at very low levels. Endosulfan is highly toxic to fish and other aquatic animals and, thus, not recommended for use in aquatic ecosystems. However, in some countries, it has been incorrectly used as a molluscicide in rice paddies, which could have an adverse impact on the rice-fish farming systems and on other surrounding aquatic ecosystems. It is clear that such practices should be stopped and users must strictly observe the recommended application methods. Agricultural productivity should be achieved with less pesticide by using integrated pest management programs which make use of biological, cultural, and physical control agents and lower doses of safer pesticide on a need only basis. The benefits of biotechnology should also be used to develop more effective and safer products and techniques. This is a valid approach and one that will require a unified and concerted effort among suppliers and users of pesticides in order to ensure that resources are used to our best advantage with minimal risk.

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There is increasing awareness that integrating gender into development frameworks is critical for effective implementation of development strategies. In working to alleviate rural poverty, the CGIAR Research Program on Aquatic Agricultural Systems (AAS) recognizes that “business as usual” gender integration approaches will not deliver lasting and widespread improvements in agricultural productivity, poverty reduction and food security. In response, AAS operationalized a gender transformative approach. The approach is informed by conceptual frameworks that explicitly recognize the potent influence of social relations on creating and perpetuating gender inequalities. In this way, AAS aims to address the underlying causes of rural poverty and gender inequality in Zambia’s Barotse Floodplain, where people rely extensively on riverine and wetland ecosystems for food and livelihood security. A central question guiding the research program is “How do social norms and gendered power relations influence agricultural development outcomes?” The findings presented in this report provide insights that help answer this question. The report presents a review of literature relevant to livelihoods, ecosystem services, and gender and social relations in Zambia, with a specific focus on Western Province, where AAS is currently implemented. It also presents a synthesis of findings of a social and gender analysis conducted in 2013 in 10 focal communities situated in and around the Barotse Floodplain.

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Nanotechnology has emerged as a technological advancement that could develop and transform the entire agri-food sector, with the potential to increase agricultural productivity, food security and economic growth for industries. Though as still a relatively new concept there are concerns over its safety, regulation and acceptance by the industry and consumers. This review set out to address the implications of nanotechnology for the agri-food industry by examining the potential benefits, risks and opportunities. Existing scientific gaps in knowledge are believed to be a prohibitive factor in addition to uncertainties in the level of awareness and attitudes towards the use of nanotechnology by the industry.

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On formal credit markets, access to formal credit and reasonable credit terms of smallholder farmers
in rural sub-Saharan Africa is limited due to adverse selection. Financial institutions operating in
rural areas often cannot distinguish between borrowers (farmers) that are creditworthy and those that
are not, thus, allocate limited resource to agriculture to reduce credit risk. In the presence of limited business quality signaling by smallholder farmers, financial institutions shall demand for collateral and/or offer unfavorable contract terms. Moreover, agricultural productivity of rural sub-Saharan
Africa, dominated by subsistence or small-scale farmers, is also negatively impacted by the adverse
effect of climate change. A strategy that may make the farming practices of smallholder farmer’s
climate resilient and profitable may also improve smallholder farmer's access to formal credit. This
study investigates to what extent participating in ecosystem and extension services (EES) programs
signals business quality of smallholders, thus granting them credit accessibility. We collected data
on 210 smallholder farmers in 2013, comprising farmers that receive payments for ecosystem
services (PES) and farm management training from the International Small Group Tree Planting
Program (TIST) Kenya to test the aforementioned theory empirically. We use game theory,
particularly a screening and sorting model, to illustrate the prospects for farmers with EES to access
formal credit and to improve their credit terms given that they receive PES and banking services
training. Furthermore, the PES’ long term duration (10 – 30 years) generates stable cash-flow which
may be perceived as collateral substitute. Results suggest that smallholder farmers in the TIST
program were less likely to be credit constraint compared to non-TIST farmers. Distance to market,
education, livestock and farm income are factors that determine access to credit from microfinance
institutions in rural Kenya. Amongst farmers that have obtained loans, those keeping business records
enjoy more favorable formal credit conditions. These farmers were observed to pay ca. 5 percent less
interest rate in microfinance charges. For TIST farmers, this type of farm management practices may
be attributed to the banking services and other training they receive within the program. While the
availability of classical collateral (farmlands) and PES may reduce interest rate, the latter was found
to be statistically insignificant. This research underlines the importance of an effective extension
services in rural areas of developing countries and the need to improve gains from conservation
agriculture and ensuing PES. The benefits associated with EES and PES may encompass agricultural
financing.

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O crescimento populacional esperado para os próximos anos conduzirá à necessidade de aumentar a produção agrícola de modo a satisfazer o aumento da procura. Nos últimos anos tem-se assistido a uma evolução tecnológica nos sistemas de produção que tem permitido aumentar a produtividade agrícola, por vezes à custa de elevados consumos de energia e com práticas nem sempre ambientalmente corretas. Os desafios que se colocam atualmente são no sentido de melhorar a conservação de recursos escassos, como o solo e a água, de aumentar a eficiência de uso de fatores de produção, de encontrar novas culturas, do desenvolvimento da biotecnologia, da diminuição dos consumos energéticos e de melhorar ainda mais as tecnologias associadas à produção. De maneira a responder aos desafios emergentes da procura por alimentos, da escassez de terrenos agrícolas aráveis bem como da existência de pragas de insetos e de ervas daninhas, os pesticidas tem vindo a ser usados com maior frequência, tendo-se assistido a uma contaminação dos solos e águas subterrâneas, causando deste modo um risco para a saúde dos seres vivos. Neste sentido, vários fabricantes de pesticidas estão a desenvolver novas formulações contendo pesticidas encapsulados em nanopartículas como modo de aumentar a sua solubilidade em água, biodisponibilidade, volatilidade, estabilidade e eficácia. tendo por objetivo um desenvolvimento sustentável. Neste trabalho, procedeu-se ao estudo do encapsulamento do herbicida Oxadiargil (5-terc-butil-3-[2,4-dicloro-5-(2-propiniloxi)fenil]-1,3,4-oxadiazol-2(3H)-ona) com a 2-hidroxipropil-β-ciclodextrina (HP-β-CD). O estudo da formação do complexo de inclusão Oxadiargil - HP-β-CD foi realizado em diferentes meios, água desionizada, tampão acetato pH = 3,46 e pH = 5,34 e tampão fosfato pH = 7,45, com o objetivo de determinar e comparar a sua constante de estabilidade. Verificou-se, em qualquer dos casos, a ocorrência de uma relação linear entre o aumento da solubilidade do Oxadiargil e o aumento da concentração de HP-β-CD, com um declive inferior a um, o que indicia a formação de um complexo na proporção estequiométrica de 1:1. Os resultados obtidos permitiram concluir que o processo de complexação Oxadiargil - HP-β-CD não é muito influenciado pela constituição e pelo pH do meio. De facto, as constantes de estabilidade obtidas para a água desionizada e soluções-tampão pH = 3,46, pH = 5,34 e pH = 7,45 foram de 919 ± 25, 685 ± 13, 623 ± 17 e 753 ± 9, respetivamente. A solubilidade do complexo obtido nos estudos realizados, em diferentes meios, é cerca de 23 a 32 vezes superior à observada para o Oxadiargil livre. De forma a caracterizar o complexo Oxadiargil - HP-β-CD procedeu-se à sua síntese utilizando o método de “kneading”. O composto obtido foi caracterizado por Ressonância Magnética Nuclear (RMN) tendo-se confirmado a formação de um complexo de inclusão na proporção estequiométrica de 1:1. O complexo obtido é mais solúvel e porventura mais estável quimicamente. O encapsulamento permite uma redução da aplicação dos pesticidas diminuindo assim os custos e o impacto negativo no ambiente. Com a nanotecnologia é possível a libertação controlada dos pesticidas, aumentando a sua eficácia e fornecendo os meios necessários para um desenvolvimento sustentável.

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L’érosion éolienne est un problème environnemental parmi les plus sévères dans les régions arides, semi-arides et les régions sèches sub-humides de la planète. L’érosion des sols accélérée par le vent provoque des dommages à la fois localement et régionalement. Sur le plan local, elle cause la baisse des nutriments par la mobilisation des particules les plus fines et de la matière organique. Cette mobilisation est une des causes de perte de fertilité des sols avec comme conséquence, une chute de la productivité agricole et une réduction de la profondeur de la partie arable. Sur le plan régional, les tempêtes de poussières soulevées par le vent ont un impact non négligeable sur la santé des populations, et la déposition des particules affecte les équipements hydrauliques tels que les canaux à ciel ouvert ainsi que les infrastructures notamment de transport. Dans les régions où les sols sont fréquemment soumis à l’érosion éolienne, les besoins pour des études qui visent à caractériser spatialement les sols selon leur degré de vulnérabilité sont grands. On n’a qu’à penser aux autorités administratives qui doivent décider des mesures à prendre pour préserver et conserver les potentialités agropédologiques des sols, souvent avec des ressources financières modestes mises à leur disposition. Or, dans certaines de ces régions, comme notre territoire d’étude, la région de Thiès au Sénégal, ces études font défaut. En effet, les quelques études effectuées dans cette région ou dans des contextes géographiques similaires ont un caractère plutôt local et les approches suivies (modèles de pertes des sols) nécessitent un nombre substantiel de données pour saisir la variabilité spatiale de la dynamique des facteurs qui interviennent dans le processus de l’érosion éolienne. La disponibilité de ces données est particulièrement problématique dans les pays en voie de développement, à cause de la pauvreté en infrastructures et des problèmes de ressources pour le monitoring continu des variables environnementales. L’approche mise de l’avant dans cette recherche vise à combler cette lacune en recourant principalement à l’imagerie satellitale, et plus particulièrement celle provenant des satellites Landsat-5 et Landsat-7. Les images Landsat couvrent la presque totalité de la zone optique du spectre exploitable par télédétection (visible, proche infrarouge, infrarouge moyen et thermique) à des résolutions relativement fines (quelques dizaines de mètres). Elles permettant ainsi d’étudier la distribution spatiale des niveaux de vulnérabilité des sols avec un niveau de détails beaucoup plus fin que celui obtenu avec des images souvent utilisées dans des études environnementales telles que AVHRR de la série de satellites NOAA (résolution kilométrique). De plus, l’archive complet des images Landsat-5 et Landsat-7 couvrant une période de plus de 20 ans est aujourd’hui facilement accessible. Parmi les paramètres utilisés dans les modèles d’érosion éolienne, nous avons identifiés ceux qui sont estimables par l’imagerie satellitale soit directement (exemple, fraction du couvert végétal) soit indirectement (exemple, caractérisation des sols par leur niveau d’érodabilité). En exploitant aussi le peu de données disponibles dans la région (données climatiques, carte morphopédologique) nous avons élaboré une base de données décrivant l’état des lieux dans la période de 1988 à 2002 et ce, selon les deux saisons caractéristiques de la région : la saison des pluies et la saison sèche. Ces données par date d’acquisition des images Landsat utilisées ont été considérées comme des intrants (critères) dans un modèle empirique que nous avons élaboré en modulant l’impact de chacun des critères (poids et scores). À l’aide de ce modèle, nous avons créé des cartes montrant les degrés de vulnérabilité dans la région à l’étude, et ce par date d’acquisition des images Landsat. Suite à une série de tests pour valider la cohérence interne du modèle, nous avons analysé nos cartes afin de conclure sur la dynamique du processus pendant la période d’étude. Nos principales conclusions sont les suivantes : 1) le modèle élaboré montre une bonne cohérence interne et est sensible aux variations spatiotemporelles des facteurs pris en considération 2); tel qu’attendu, parmi les facteurs utilisés pour expliquer la vulnérabilité des sols, la végétation vivante et l’érodabilité sont les plus importants ; 3) ces deux facteurs présentent une variation importante intra et inter-saisonnière de sorte qu’il est difficile de dégager des tendances à long terme bien que certaines parties du territoire (Nord et Est) aient des indices de vulnérabilité forts, peu importe la saison ; 4) l’analyse diachronique des cartes des indices de vulnérabilité confirme le caractère saisonnier des niveaux de vulnérabilité dans la mesure où les superficies occupées par les faibles niveaux de vulnérabilité augmentent en saison des pluies, donc lorsque l’humidité surfacique et la végétation active notamment sont importantes, et décroissent en saison sèche ; 5) la susceptibilité, c’est-à-dire l’impact du vent sur la vulnérabilité est d’autant plus forte que la vitesse du vent est élevée et que la vulnérabilité est forte. Sur les zones où la vulnérabilité est faible, les vitesses de vent élevées ont moins d’impact. Dans notre étude, nous avons aussi inclus une analyse comparative entre les facteurs extraits des images Landsat et celles des images hyperspectrales du satellite expérimental HYPERION. Bien que la résolution spatiale de ces images soit similaire à celle de Landsat, les résultats obtenus à partir des images HYPERION révèlent un niveau de détail supérieur grâce à la résolution spectrale de ce capteur permettant de mieux choisir les bandes spectrales qui réagissent le plus avec le facteur étudié. Cette étude comparative démontre que dans un futur rapproché, l’amélioration de l’accessibilité à ce type d’images permettra de raffiner davantage le calcul de l’indice de vulnérabilité par notre modèle. En attendant cette possibilité, on peut de contenter de l’imagerie Landsat qui offre un support d’informations permettant tout de même d’évaluer le niveau de fragilisation des sols par l’action du vent et par la dynamique des caractéristiques des facteurs telles que la couverture végétale aussi bien vivante que sénescente.

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Little is known about the sustainability of irrigated oasis agriculture in northern Oman. The objective of this study therefore was to examine which factors allowed agricultural productivity to be apparently maintained during the two millenia of a mountain oasis’ existence. Soil moisture and physico-chemical properties were measured in a typical flood-irrigated field sown to alfalfa (Medicago sativa L.). Particle size, organic (C_org) and inorganic carbon content, pH and electrical conductivity (EC)of the soil profile were analyzed at 0.15, 0.45 and 1.00 m. Saturated hydraulic conductivity and the soil’s apparent bulk density and water potential were determined from undisturbed samples at 0.05, 0.25 and 0.60 m. During irrigation cycles of 6–9 days, volumetric water contents ranged from 30% to 13%. A tracer experiment with potassium bromide revealed that 52–56% of the irrigation water was stored in the upper 0.4 m of the soil. The rest of the water moved further down the profile, thus providing the necessary drainage to avoid the build-up of toxic salt concentrations. Due to differences in pore size, plant-available water in the topsoil amounted to 18.7% compared to 13% and 13.5% at 0.25- and 0.60-m depth, respectively. The aggregate structure in the upper 1.0 m of the profile is likely preserved by concentrations of calcium carbonate (CaCO3) from 379 to 434 mg kg^-1 and C_org from 157 to 368 mg kg^-1 soil. The data indicate that the sustainability of this irrigated landuse system is due to high water quality with low sodium but high CaCO3 concentration, the elaborate terrace structure and water management which allows adequate drainage.

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Little is known about gaseous carbon (C) and nitrogen (N) emissions from traditional terrace agriculture in irrigated high mountain agroecosystems of the subtropics. In an effort towards filling this knowledge gap measurements of carbon dioxide (CO_2), methane (CH_4), ammonia (NH_3) and dinitrous oxide (N_2O) were taken with a mobile photoacoustic infrared multi-gas monitor on manure-filled PE-fibre storage bags and on flood-irrigated untilled and tilled fields in three mountain oases of the northen Omani Al Jabal al Akhdar mountains. During typical 9-11 day irrigation cycles of March, August and September 2006 soil volumetric moisture contents of fields dominated by fodder wheat, barley, oats and pomegranate ranged from 46-23%. While manure incorporation after application effectively reduced gaseous N losses, prolonged storage of manure in heaps or in PE-fibre bags caused large losses of C and N. Given the large irrigation-related turnover of organic C, sustainable agricultural productivity of oasis agriculture in Oman seems to require the integration of livestock which allows for several applications of manure per year at individual rates of 20 t dry matter ha^−1.

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The Upper Blue Nile River Basin (UBNRB) located in the western part of Ethiopia, between 7° 45’ and 12° 45’N and 34° 05’ and 39° 45’E has a total area of 174962 km2 . More than 80% of the population in the basin is engaged in agricultural activities. Because of the particularly dry climate in the basin, likewise to most other regions of Ethiopia, the agricultural productivity depends to a very large extent on the occurrence of the seasonal rains. This situation makes agriculture highly vulnerable to the impact of potential climate hazards which are about to inflict Africa as a whole and Ethiopia in particular. To analyze these possible impacts of future climate change on the water resources in the UBNRB, in the first part of the thesis climate projection for precipitation, minimum and maximum temperatures in the basin, using downscaled predictors from three GCMs (ECHAM5, GFDL21 and CSIRO-MK3) under SRES scenarios A1B and A2 have been carried out. The two statistical downscaling models used are SDSM and LARS-WG, whereby SDSM is used to downscale ECHAM5-predictors alone and LARS-WG is applied in both mono-model mode with predictors from ECHAM5 and in multi-model mode with combined predictors from ECHAM5, GFDL21 and CSIRO-MK3. For the calibration/validation of the downscaled models, observed as well as NCEP climate data in the 1970 - 2000 reference period is used. The future projections are made for two time periods; 2046-2065 (2050s) and 2081-2100 (2090s). For the 2050s future time period the downscaled climate predictions indicate rise of 0.6°C to 2.7°C for the seasonal maximum temperatures Tmax, and of 0.5°C to 2.44°C for the minimum temperatures Tmin. Similarly, during the 2090s the seasonal Tmax increases by 0.9°C to 4.63°C and Tmin by 1°C to 4.6°C, whereby these increases are generally higher for the A2 than for the A1B scenario. For most sub-basins of the UBNRB, the predicted changes of Tmin are larger than those of Tmax. Meanwhile, for the precipitation, both downscaling tools predict large changes which, depending on the GCM employed, are such that the spring and summer seasons will be experiencing decreases between -36% to 1% and the autumn and winter seasons an increase of -8% to 126% for the two future time periods, regardless of the SRES scenario used. In the second part of the thesis the semi-distributed, physically based hydrologic model, SWAT (Soil Water Assessment Tool), is used to evaluate the impacts of the above-predicted future climate change on the hydrology and water resources of the UBNRB. Hereby the downscaled future predictors are used as input in the SWAT model to predict streamflow of the Upper Blue Nile as well as other relevant water resources parameter in the basin. Calibration and validation of the streamflow model is done again on 1970-2000 measured discharge at the outlet gage station Eldiem, whereby the most sensitive out the numerous “tuneable” calibration parameters in SWAT have been selected by means of a sophisticated sensitivity analysis. Consequently, a good calibration/validation model performance with a high NSE-coefficient of 0.89 is obtained. The results of the future simulations of streamflow in the basin, using both SDSM- and LARS-WG downscaled output in SWAT reveal a decline of -10% to -61% of the future Blue Nile streamflow, And, expectedly, these obviously adverse effects on the future UBNRB-water availibiliy are more exacerbated for the 2090’s than for the 2050’s, regardless of the SRES.

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Facing the double menace of climate change threats and water crisis, poor communities have now encountered ever more severe challenges in ensuring agricultural productivity and food security. Communities hence have to manage these challenges by adopting a comprehensive approach that not only enhances water resource management, but also adapts agricultural activities to climate variability. Implemented by the Global Environment Facility’s Small Grants Programme, the Community Water Initiative (CWI) has adopted a distinctive approach to support demand-driven, innovative, low cost and community-based water resource management for food security. Experiences from CWI showed that a comprehensive, locally adapted approach that integrates water resources management, poverty reduction, climate adaptation and community empowerment provides a good model for sustainable development in poor rural areas.

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Avaluació de l’efecte del tipus de tràfic imposat a les vaques lleteres en sistemes de munyida automàtica sobre la freqüència de munyida, les necessitats d’alimentació, el comportament alimentari i la producció i composició de la llet

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Las estrategias tendientes a la diversificación de los mercados de exportación e internacionalización de la economía por parte del gobierno colombiano y sus políticas gubernamentales han incluido la firma de una serie de Tratados de Libre Comercio, entre ellos el TLC de última generación firmado con El Estado de Israel. Estos tratados además de abordar temas tradicionales de comercio, tratan nuevos capítulos en inversiones y servicios. Así mismo se analizan las principales políticas por parte del gobierno de Israel para la competitividad en términos empresariales y sociales. Más adelante se consideran aspectos generales de la economía colombiana y se analiza la relación comercial bilateral entre el Estado de Israel y la República de Colombia para entender su comportamiento histórico y el ambiente actual. Finalmente se hace un énfasis en el sector agrícola de Israel y sus aspectos que lo han dirigido al éxito, una observación corta del sector en Colombia y luego aspectos adicionales para a facilitación del comercio con Israel. El estudio va dirigido a empresarios, compañías o entes públicos a nivel local e internacional que vean en el sector agrícola colombiano una oportunidad de desarrollo, aprovechando los beneficios de comercio y conocimiento, con el objetivo de mejorar la competitividad y productividad del sector en Colombia. Se utilizan metodologías tanto cuantitativas como cualitativas para la investigación y análisis de caso tomando la información correspondiente de fuentes verídicas e independientes para así poder reseñar y describir las oportunidades y retos del sector agrícola.

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El objetivo principal de esta monografía es identificar cuáles son las razones que justifican las contradicciones entre el discurso y el comportamiento de Estados Unidos en el marco de la Organización Mundial del Comercio, particularmente con relación a prácticas anticompetitivas derivadas del programa de protección a la agricultura del país. Para ello se analizan el interés nacional y los elementos de la seguridad nacional a partir de los cuales éste se ha construido. También se evalúan los procesos de formulación de política comercial y las interacciones entre los representantes políticos, las asociaciones de productores y el sector privado para mostrar como este comportamiento contradictorio corresponde a la legitimización de un interés particular.

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Projections of climate change impacts on crop yields are inherently uncertain1. Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate2. However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop simulation models1, 3 are difficult4. Here we present the largest standardized model intercomparison for climate change impacts so far. We found that individual crop models are able to simulate measured wheat grain yields accurately under a range of environments, particularly if the input information is sufficient. However, simulated climate change impacts vary across models owing to differences in model structures and parameter values. A greater proportion of the uncertainty in climate change impact projections was due to variations among crop models than to variations among downscaled general circulation models. Uncertainties in simulated impacts increased with CO2 concentrations and associated warming. These impact uncertainties can be reduced by improving temperature and CO2 relationships in models and better quantified through use of multi-model ensembles. Less uncertainty in describing how climate change may affect agricultural productivity will aid adaptation strategy development andpolicymaking.